JUGLANDACEAE 333 



Leaflets with lanceolate or narrowly-lanceolate blades : fruits 5-8 cm. in diameter. 2. J. nigra. 

 Leaflets with ovate or ovate-lanceolate blades : fruits about 2 cm. in diameter. 3. J. rupestris. 



1. Juglans cinerea L. A tree, reaching a maximum height of about 30 m., with a 

 trunk diameter of 1 m. , the heart-wood pale, the bark light brown. Leaves 3-6 dm. long, with 

 stout pubescent petioles ; leaflets 11-17, the blades lanceolate or oblong-lanceolate or oblong, 

 6-12 cm. long, acute or acuminate at the apex, serrate, inequilateral at the base, sessile or 

 short-stalked, viscid-pubescent, but at length glabrous above : staminate aments 6-15 cm. 

 long : anther with an apiculate appendage : fruits spicate, oblong, 8-12 cm. long, usually 

 acute, very viscid-pubescent : nut shaped like the husk, 1-celled above, 2-celled below the 

 middle, the surface sculptured into thin brittle irregular longitudinal ridges. 



In moist soil or rich woods, New Brunswick to North Dakota, Georgia, Alabama, Arkansas and 

 Nebraska. BUTTERNUT. WHITE WALNUT. 



2. Juglans nigra L. A forest tree, reaching a maximum height of 50 m. and a trunk 

 diameter of 2.5 m., producing a dark brown heart-wood, the bark dark brown, broken into 

 broad ridges. Leaves 3-6 dm. long, with stout pubescent petioles ; leaflets 15-23 (the ter- 

 minal one often suppressed), the blades 8-10 cm. long, ovate or ovate-lanceolate, acute or 

 acuminate, serrate, rounded or subcordate at the inequilateral base, sessile or nearly so, 

 becoming glabrous above, pubescent beneath : staminate aments 5-10 cm. long : anther 

 tipped by the dilated connective : fruits globose or globose-ovoid, 5-8 cm. long, rounded at 

 the apex, glabrous : nut globose-ovoid, slightly flattened, sometimes broader than high, 

 2-celled above, 4-celled below the middle, the surface sculptured into thick irregular 

 ridges. 



In rich soil, Massachusetts to Ontario and Minnesota, Florida, Texas and Nebraska. WALNUT. 

 BLACK WALNUT. 



3. Juglans rup6stris Engelm. A small tree, sometimes reaching a height of 16 m. 

 and a trunk diameter of 1.5m., the bark pale, deeply furrowed. Leaves 2-3 dm. long, with 

 slender pubescent petioles ; leaflets 9-23, the blades lanceolate or narrowly-lanceolate, 

 acuminate, distantly serrate with appressed rather blunt teeth, often scythe-shaped, inequi- 

 lateral, especially near the base, short-stalked, pubescent when young, usually becoming 

 glabrous in age : staminate aments 5-1 Ocm. long: anther tipped by the dilated connec- 

 tive : fruits globose, about 2 cm. in diameter, solitary, or often 2 together, glabrous : 

 nut subglobose, grooved, 4-celled below the middle. 



In valleys, middle Texas to New Mexico and northern Mexico. WALNUT. 



2. HICORIA Kaf. 



Trees, cylindric in outline, with hard and very tough wood, a watery sap, and a close 

 or scaly bark. Pith solid. Leaflets involute in vernation : blades usually leathery. 

 Staminate aments often branched, clustered on the twigs of the preceding year or at the 

 base of the twigs of the present year, mostly long-stalked : calyx 3-lobed or rarely 2-lobed, 

 subtended by an almost free bract ; this longer than the calyx-lobes : stamens 3-10, in 

 several rows : anthers 2-celled, pubescent, each notched at the apex ; sacs opening length- 

 wise, with an inconspicuous connective. Pistillate flowers in spike-like clusters at the ends 

 of the twigs of the present year : calyx of 1 sepal adnate on the ovary : ovary inferior : 

 stigmas spreading. Fruit subglobose, obovoid or cylindric : husk becoming dry, 4-valved, 

 splitting more or less readily to the middle or base, its angles sometimes winged : nut 

 smooth, thin-walled or thick-walled, more or less flattened. Seed sweet or bitter. \_Carya 

 Nutt.] The plants flower in the spring and mature their fruit in the fall. 



Cotyledons entire or merely notched at the apex : nuts terete or slightly flattened, smooth and even. 

 Leaflets 5-9 : nuts with exceedingly thick shells. 1. H. myristicaeformis. 



Leaflets 9-15 : nuts with thin shells. 



Leaflets with stalked blades : nut terete : seed sweet. 2. //. Pecan. 



Leaflets with sessile or nearly sessile blades : nuts flattened : seed bitter. 3. If. Texana. 

 Cotyledons deeply 2-lobed : nuts markedly flattened, usually uneven. 

 Bud-scales valvate : lateral leaflets mostly falcate. 



Leaflets 9-13, glabrous : nuts corrugated. 4. H. aquatica. 



Leaflets 5-9, pubescent beneath : nuts smooth. 5. H. minima. 



Bud-scales imbricated : lateral leaflets not falcate. 



* Middle lobe of the staminate calyx, much larger than the lateral : husk 

 of the fruit freely splitting to "the base. 

 Bark close, but rough : foliage scurfy or pubescent. 



Rachis of the leaves and staminate aments scurfy pubescent at least 



when young. 6. H. pallida. 



Rachis of the leaves and staminate aments densely hirsute. 7. //. alba. 



Bark shaggy, separating in long plates : foliage glabrous or puberulent. 



t Leaflets 7-9 : nuts pointed at both ends. 8. H. laciniosa. 



